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Mitigating Uncertainty in Developing and Applying Scientific Applications in an Integrated Computing Environment

programming AND COMPUTER SOFTWARE 2020年第8期46卷 483-502页

作者： Tchernykh, A. Bychkov, I. Feoktistov, A. Gorsky, S. Sidorov, I. Kostromin, R. Edelev, A. Zorkalzev, V. Avetisyan, A. CICESE Res Ctr Carr Tijuana Ensenada 3918 Ensenada 22860 Baja California Mexico South Ural State Univ Chelyabinsk 454080 Russia RAS Ivannikov Inst Syst Programming Moscow 109004 Russia RAS SB Matrosov Inst Syst Dynam & Control Theory Irkutsk 664033 Russia RAS SB Melentiev Energy Syst Inst Irkutsk 664033 Russia RAS SB Limnol Inst Irkutsk 664033 Russia

Effective solving complex mathematical modeling problems is based on the use of high-performance computing. Clouds, grids, and public access supercomputer centers are commonly used platforms. Their integration into a unified environment provides possibilities for carrying out mass large-scale scientific experiments and efficient scalable resource allocation at different stages of the application design and execution. However, end-users have to carefully select optimization criteria such as completion time, deadlines, reliability, cost, etc. It is a complicated problem due to integrated resources differ significantly in their computing capabilities, hardware and software platforms, system architectures, user interfaces, etc. The paper presents new features of the Orlando Tools framework for the development of distributed applied software packages (scalable scientific applications) that mitigates various types of uncertainties arising from the job distribution in the integrated computing environment. It provides continuous integration, delivery, and deployment of applied and system software to significantly mitigate the negative impact of uncertainty on problem-solving time, computation reliability, and resource efficiency. An experimental analysis of the sustainable design and development of the real energy sector clearly demonstrates the advantages of the tools.

关键词： Supercomputers

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Using Ansible as Part of TOSCA Orchestrator

Using Ansible as Part of TOSCA Orchestrator

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Ivannikov Ispras Open Conference (ISPras)

作者： Shvetcova, Valeriya Borisenko, Oleg Polischuk, Maxim RAS Ivannikov Inst Syst Programming Moscow Russia Bauman Moscow State Tech Univ Moscow Russia

ISBN: (纸本)9781665412919

Cloud computing is used in many areas and by many specialists to ease application distribution and deployment. Cloud providers basically aim at providing resources varying from others. So it becomes very difficult to deploy multicloud applications or move to the cloud from own hardware clusters. TOSCA standard offers cloud resources model that unifies many cloud providers. In this paper we propose TOSCA orchestrator Clouni. Clouni takes TOSCA templates from the user and generates Ansible playbooks. Ansible is then used as a configuration tool for deployment automation. Clouni makes it easy for cloud users to deploy complex topologies.

关键词： TOSCA Ansible Infrastructure as code cloud portability cloud computing deployment automation

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Bit complexity of computing solutions for symmetric hyperbolic systems of PDEs with guaranteed precision

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COMPUTABILITY-THE JOURNAL OF THE ASSOCIATION CIE 2021年第2期10卷 123-140页

作者： Selivanova, Svetlana Selivanov, Victor Korea Adv Inst Sci & Technol Sch Comp 291 Daehak Ro Daejeon 34141 South Korea AP Ershov Inst Informat Syst SB RAS Theoret Programming Lab 6 Acad Lavrentjev Pr Novosibirsk 630090 Russia

We establish upper bounds on bit complexity of computing solution operators for symmetric hyperbolic systems of PDEs, combining symbolic and approximate algorithms to obtain the solutions with guaranteed prescribed pr... 详细信息

关键词： Symmetric hyperbolic system bit complexity solution operator guaranteed precision symbolic computations algebraic real approximation symmetric matrix spectral decomposition difference scheme

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Research on the wake of the ducted propeller with POD and DMD

Research on the wake of the ducted propeller with POD and DM...

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Ivannikov Ispras Open Conference (ISPras)

作者： Wang, Tianyuan Shi, Hongda Zhang, Qin Yang, Bo Liu, Xin Matvey, Kraposhin Ocean Univ China Coll Engn Qingdao Peoples R China RAS Ivannikov Inst Syst Programming Moscow Russia

ISBN: (纸本)9781665412919

The paper attempts to apply the Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) to the ducted propeller wake analysis. The ducted propeller produces a complex wake flow field with multifrequency vortex structure coupling under the influence between blades and nozzle. Traditional analysis methods such as time-averaged flow, phase-averaged flow are only displaying the coupling results. In contrast, data mining technologies such as POD and DMD can extract independent flow patterns from the massive data obtained from physical experiments and numerical simulations. The paper focuses on the influence of computational subdomain (based on the OpenFOAM), snapshot sampling interval and data coverage revolutions on the modal convergence in the data preprocessing before employing POD and DMD. Taking a single ducted propeller wake data with the advance coefficient of J=0.4 as an example, it is found that the sampling interval of snapshots are independent of modal convergence after reaching a certain level and only affect the frequency range of the captured modes. The scope of the computational subdomain and the revolutions of data covered by snapshot matrix are vital factors to affect the modal convergence. At last, under the premise of modal convergence, the paper reconstructs the ducted propeller wake flow field by POD and DMD respectively, where errors between the original data can be ignored.

关键词： POD DMD the ducted propeller wake the OpenFOAM

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RRNS Base Extension Error-Correcting Code for Performance Optimization of Scalable Reliable Distributed Cloud Data Storage

RRNS Base Extension Error-Correcting Code for Performance Op...

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35th IEEE International Parallel and Distributed Processing Symposium (IPDPS)

作者： Babenko, Mikhail Tchernykh, Andrei Pulido-Gaytan, Bernardo Cortes-Mendoza, Jorge M. Shiryaev, Egor Golimblevskaia, Elena Avetisyan, Arutyun Nesmachnow, Sergio North Caucasus Fed Univ Stavropol Russia CICESE Res Ctr Ensenada Baja California Mexico South Ural State Univ Chelyabinsk Russia RAS Ivannikov Inst Syst Programming Moscow Russia Univ Republica Montevideo Uruguay

ISBN: (纸本)9781665435772

Ensuring reliable data storage in a cloud environment is a challenging problem. One of the efficient mechanisms used to solve it is the Redundant Residue Number system (RRNS) with the projection method, a commonly used mechanism for detecting errors. However, the error correction based on the projection method has exponential complexity depending on the number of control and working moduli. In this paper, we propose an optimization mechanism using a base extension and Hamming distance to reduce the number of calculated projections. We show that they can be reduced up to three times than the classical projection method and, hence, the time complexity of data recovery in the distributed cloud data storage.

关键词： cloud computing residue number system reliability error-correcting code uncertainty

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Numerical investigation of flow around two cylinders in tandem above a scoured bed

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PHYSICS OF FLUIDS 2022年第8期34卷

作者： Yang, Bo Liang, Bingchen Zhang, Qin Meng, Xun Matvey, Kraposhin Epikhin, Andrey Ocean Univ China Coll Engn Qingdao Peoples R China Ocean Univ China Shandong Prov Key Lab Ocean Engn Qingdao Peoples R China RAS Ivannikov Inst Syst Programming Moscow Russia

Flow mechanisms around two cylinders in tandem arrangement above a scoured bed have been investigated using the three-dimensional unsteady Navier-Stokes equations with the Spalart-Allmaras improved delayed detached-eddy simulation model. A turbulent inlet boundary layer generation method is adopted to obtain more realistic inlet boundary conditions. First, uniform flow over a single cylinder at Re = 3900 and flow over a single cylinder above scoured beds at Re = 6000 were simulated to validate the numerical model, boundary layer generation method, and mesh density effect. Second, two cylinders in the tandem arrangement above scoured beds with six different pitch ratios L/D are investigated numerically in terms of instantaneous vortex characteristics, the hydrodynamic force, and time-averaged flow fields. The simulation results in scoured beds are compared with simulations under the near flat wall and wall-free conditions. The major findings can be summarized as follows. (1) When L / D & LE;2.0, the wake of two tandem cylinders is dominated by the intermittent shedding, and the downstream sand dune in the scoured bed hinders the Karman vortex formation at the rear of the downstream cylinder. Lift force fluctuations of the two cylinders have small amplitudes, and their spectra show a multi-peak distribution and no dominant peak frequency in the spectrum of the upstream cylinder. A squarish cavity-like recirculation zone is formed between two cylinders at L / D <= 2.0. (2) When L / D >= 3.0, the periodic vortex shedding is evident in the wake of the upstream cylinder, and the small sand berm between two cylinders has an impact on the bottom shear layer of the upstream cylinder. The downstream cylinder is periodically impacted by the vortices shed from the upstream cylinder. Lift force spectra of the upstream and downstream cylinders have the same peak frequency. (3) Due to the influence of scoured bed and the inlet boundary layer, the time-averaged lift coefficient of

关键词： Wakes

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Prediction of the Free Jet Noise Using Quasi-gas Dynamic Equations and Acoustic Analogy 20th

Prediction of the Free Jet Noise Using Quasi-gas Dynamic Equ...

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20th Annual International Conference on Computational Science (ICCS)

作者： Epikhin, Andrey Kraposhin, Matvey RAS Ivannikov Inst Syst Programming Moscow 109004 Russia Bauman Moscow State Tech Univ Moscow 105005 Russia RAS Keldysh Inst Appl Math Moscow 125047 Russia

ISBN: (纸本)9783030504366;9783030504359

The paper is focused on the numerical simulation of acoustic properties of the free jets from circle nozzle at low and moderate Reynolds numbers. The near-field of compressible jet flow is calculated using developed regularized (quasi-gas dynamic) algorithms solver QGDFoam. Acoustic noise is computed for jets with M = 0.9, Re = 3600 and M = 2.1, Re = 70000 parameters. The acoustic pressure in far field is predicted using the Ffowcs Williams and Hawkings analogy implemented in the libAcoustics library based on the OpenFOAM software package. The determined properties of the flow and acoustic fields are compared with experimental data. The flow structures are characterized by the development of the Kelvin-Helmholtz instability waves, which lead to energy outflux in the radial direction. Their further growth is accompanied by the formation of large and small-scale eddies leading to the generation of acoustic noise. The results showed that for selected jets the highest levels of generated noise is obtained at angles around 30 degrees which agrees well with experimental data.

关键词： Aeroacoustics Jet Noise Regularized equations OpenFOAM

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Lower Bounds and Optimal Algorithms for Smooth and Strongly Convex Decentralized Optimization Over Time-Varying Networks 35

Lower Bounds and Optimal Algorithms for Smooth and Strongly ...

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35th Conference on Neural Information Processing systems (NeurIPS)

作者： Kovalev, Dmitry Gasanov, Elnur Gasnikov, Alexander Richtarik, Peter King Abdullah Univ Sci & Technol Thuwal Saudi Arabia MIPT Moscow Russia ISP RAS Moscow Russia Moscow Inst Phys & Technol Moscow Russia Russian Acad Sci Res Ctr Trusted Artificial Intelligence Inst Syst Programming Moscow Russia

ISBN: (纸本)9781713845393

We consider the task of minimizing the sum of smooth and strongly convex functions stored in a decentralized manner across the nodes of a communication network whose links are allowed to change in time. We solve two fundamental problems for this task. First, we establish the first lower bounds on the number of decentralized communication rounds and the number of local computations required to find an.-accurate solution. Second, we design two optimal algorithms that attain these lower bounds: (i) a variant of the recently proposed algorithm ADOM (Kovalev et al., 2021) enhanced via a multi-consensus subroutine, which is optimal in the case when access to the dual gradients is assumed, and (ii) a novel algorithm, called ADOM+, which is optimal in the case when access to the primal gradients is assumed. We corroborate the theoretical efficiency of these algorithms by performing an experimental comparison with existing state-of-the-art methods.

关键词： Time varying networks

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Sydr: Cutting Edge Dynamic Symbolic Execution

Sydr: Cutting Edge Dynamic Symbolic Execution

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Ivannikov Ispras Open Conference (ISPras)

作者： Vishnyakov, Alexey Fedotov, Andrey Kuts, Daniil Novikov, Alexander Parygina, Darya Kobrin, Eli Logunova, Vlada Belecky, Pavel Kurmangaleev, Shamil RAS Ivannikov Inst Syst Programming Moscow Russia Lomonosov Moscow State Univ Moscow Russia Moscow Inst Phys & Technol Moscow Russia

ISBN: (纸本)9781665412919

The security development lifecycle (SDL) is becoming an industry standard. Dynamic symbolic execution (DSE) has enormous amount of applications in computer security (fuzzing, vulnerability discovery, reverse-engineering, etc.). We propose several performance and accuracy improvements for dynamic symbolic execution. Skipping non-symbolic instructions allows to build a path predicate 1.2-3.5 times faster. Symbolic engine simplifies formulas during symbolic execution. Path predicate slicing eliminates irrelevant conjuncts from solver queries. We handle each jump table (switch statement) as multiple branches and describe the method for symbolic execution of multi-threaded programs. The proposed solutions were implemented in Sydr tool. Sydr performs inversion of branches in path predicate. Sydr combines DynamoRlO dynamic binary instrumentation tool with Triton symbolic engine. We evaluated Sydr features on 64-bit Linux executables.

关键词： symbolic execution concolic execution dynamic analysis binary analysis dynamic binary instrumentation computer security security development lifecycle DSE SMT DBI SDL

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On the Calculation of the Vortex Sheet and Point Vortices Effects at Approximate Solution of the Boundary Integral Equation in 2D Vortex Methods of Computational Hydrodynamics

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FLUID DYNAMICS 2019年第7期54卷 991-1001页

作者： Kuzmina, K. S. Marchevskii, I. K. Bauman Moscow State Syst Univ Moscow Russia RAS Ivannikov Inst Syst Programming Moscow Russia

When simulating incompressible flow around airfoil using vortex methods of computational hydrodynamics, it is necessary to solve the boundary integral equation with respect to the intensity of the vortex sheet at the airfoil surface line. For its approximate solution, the Galerkin method with a piecewise-constant and piecewise-linear representation of the solution on the airfoil surface line can be applied. The coefficients of the system of linear equations, arising from the procedure of discretization of the integral equation, e xpress the influence of the vortex sheet located on the panels of the airfoil surface line on other panels;the components of the right-hand side vector express the influence of point vortices that simulate a vortex wake in the flow domain. For the case of the airfoil surface line approximation with a polyline consisting of rectilinear panels, exact analytical expressions are obtained for the coefficients of the matrix and the right-hand side vector;for the case of taking into account the curvature of the panels, an approach for their approximate calculation is proposed and all the necessary formulae are derived.

关键词： vortex methods boundary integral equation computational hydrodynamics

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